Pion-Exchange Effects in Elastic Backward Proton-Deuteron Scattering

 The elastic backward proton-deuteron scattering is analyzed within a covariant approach based on the deuteron vertex function obtained by the Bethe-Salpeter equation with realistic meson-exchange interaction. Contributions of the one-nucleon and one-pion exchange mechanisms to the cross section and polarization observables are investigated in explicit form. Results of numerical calculations for the cross section, tensor analyzing power and spin transfers are presented. The one-pion exchange contribution is essential for describing the spin-averaged cross section, while in polarization observables it is found to have a small effect. Received December 22, 1998; revised November 8, 1999; accepted November 10, 1999     

Complete Set of Deuteron Analyzing Powers for dp Elastic Scattering at Intermediate Energies and Three Nucleon Forces

With the aim of clarifying roles of the 3NFs in nuclei experimental programs with the polarized deuteron beam at intermediate energies are in progress at RIKEN RI Beam Factory. As the first step, we have measured a complete set of deuteron analyzing powers in deuteron–proton elastic scattering at 250 and 294 MeV/nucleon. The obtained data are compared with the Faddeev calculations based on the modern nucleon–nucleon forces together with the Tucson–Melbourne’99, and UrbanaIX three nucleon forces.     

Hyperon-Neutron Elastic Scattering

It is shown that the Chou-Yang model can be extended to hyperon-neutron elastic reactions at high energies by assuming that the hadronic form factor of neutron is proportional to its magnetic form factor. It is also predicted that the scaling of magnetic form factor of neutron with charge as well as magnetic form factors of proton implies that the differential cross sections of corresponding hyperon-proton and hyperon-neutron reactions should be equal.     

On the K^＋—^6Li Elastic Scattering

Total and differential cross sections for K^ -^6Li elastic scattering are calculated using the folding optical potential model,in which the influence of three factors is considered including the recoil of target nucleus,the loosely bounded nuclear density and the unusual spin of ^6Li ground state.The theoretical results are found in pretty good accordance with the existing experimental data at PK=715 MeV/c.     

The Phase Shifts for A-N Elastic Scattering

chiral soliton model with the gluon field, chiral doublet (σ, π)-field and chird singlet ω-meson field is employed to study A-nucleon elastic scattering phase shifts within the framework of the relativistic two-quark-cluster theory. The phase shifts are sensitive to the strange quark in the A-hyperon.     

有核细胞的弹性光散射模型

提出一种新型的同心椭球构成的同心椭球（CEM）模型来模拟有核细胞,以瑞利-德拜-甘斯（Rayleigh-Debye-Gans）近似理论为基础,对细胞内不同部分的传播常量加以修正,用该模型代替球系列模型,研究其光散射特性。结果表明同心椭球模型更精确地反映了非球形有核细胞光散射的真实情况,同时其前向、侧向及后向光散射精细谱的呈现,可以在庞杂的细胞中辨别不同的细胞类型,较好的应用于细胞的变形性研究和细胞分类研究的领域。     

α粒子散射实验与原子核的发现——"最美丽"的十大物理实验之三

1实验背景 自1897年汤姆孙(J.J.Thomson 1856～1940年)从实验中发现电子;1896年亨利·贝克勒(H.A.Becquere1 1852～1908年)发现铀的放射性现象;1898年居里夫人(M.Curie 1867～1934年)发现镭的放射性现象;1897年卢瑟福(E.Rutherford 1871～1937年,英藉新西兰人)发现放射性中的α射线和β射线;1900年维拉德(P.U.Villard 1860～1934年)发现放射性中第三种射线--γ射线以后,使人们认识到原子是可分的,原子是有结构的.因此,各国物理学家们便开始探索原子的复杂结构.     

Angular Dispersion and Deflection Function for Heavy Ion Elastic Scattering

The differential cross sections for elastic scattering products of ^17F on ^208Pb have been measured. The angular dispersion plots of ln（dσ/dθ） versus θ^2 are obtained from the angular distribution of the elastic scattering differential cross sections. Systematical analysis on the angular dispersion for the available experimental data indicates that there is an angular dispersion turning angle at forward angular range within the grazing angle. This turning angle can be clarified as nucleal rainbow in classical deflection function. The exotic behaviour of the nuclear rainbow angle offers a new probe to investigate the halo and skin phenomena.     

K-Nucleus Elastic Scattering and Momentum-Dependent Optical Potentials

The K-nucleus differential elastic scattering cross section for 12C and 40 Ca at pκ = 800 Me V/c is calculated with three momentum-dependent optical potential models,which are density-dependent,relativistic mean field,and hybrid model,respectively.It is found that the forms of momentum-dependent optical potential models proposed by us are reasonable and gain success in the calculations and the momentum-dependent hybrid model is the best model for the K- nucleus elastic scattering.     

Laser-Assisted Elastic Electron Scattering from Argon

The second Born approximation （SBA） theory is applied to the study of electron-atom scattering in the presence of a CO2 laser field.The absolute differential crass sections of e-Ar scattering are calculated with multiphoton exchange in two special scattering geometries G1 （for small-angle scattering） and G2. For geometry G1, compared with the results of two different model potentials for electron elastic scattering by atoms, it is found that electronatom polarization potential plays an important role in laser-assisted electron-atom scattering. Some calculational results in geometries G2 are given. Our results are found to be better than other theoretical results as compared with the experimental data in geometries G1 and G2.     

Polarization Phenomena in Elastic Electron-Proton Scattering

A unified treatment is given by using the scattering matrix in the Pauli spin spaces and polarization density matrices. Various quantities such as polarization P, asymmetry A, spin correlation parameters C_αβ, double polarization asymmetry A_αβ, polarization transfer parameters D_t, A_t, R_t and depolarization and spin rotation parameters D, A, R are expressed in terms of six coefficients which appear in the scattering matrix. Some explicit expressions as well as numerical results for these quantities are also given in the one photon exchange approximation.     

Proton Elastic Scattering of23,25F

Proton elastic scatterings of neutron-rich nuclei ²³F and ²⁵F have been measured for the first time at 289 and 298 MeV/nucleon, respectively, using the MUST2 silicon strip detector array and RIBF facility at RIKEN. The differential cross section of ²⁵F was found to be smaller than the calculation with the global potential by Koning and Deraloche. The small cross section of ²⁵F can be well reproduced by an optical model calculation with a shallow and long-tail potential.     

Ab-Initio Calculations of Four-Nucleon Elastic Scattering

We present microscopic calculations of low-energy scattering observables in all possible four-nucleon systems: n-³H, p-³He, and p-³H. Results were obtained by solving Faddeev-Yakubovski equations in configuration space, appropriately modified to include Coulomb and three-nucleon forces.     

Consequences of Crossed Channel Structure for High Energy Elastic Scattering

This review describes a field in the S-matrix theory of elastic stattering. Analyticity and elastic unitarity in the crossed t-channel are shown in a rigorous manner to yield constraints on s-channel quantities. Strong restrictions on s-channel partial wave with angular momenta l ⩾√s/2(b₀ + λ In s) follow from realistic assumptions on the amplitude in the unphysical domain (Mandelstam analyticity and Regge behaviour). The possibility of phenomenological application of these results is discussed.     

A Proof of Haag-Swieca's Compactness Property for Elastic Scattering States

 It is proved that in any massive relativistic quantum field theory satisfying two-particle asymptotic completeness, all the bounded energy components in the elastic two-particle range of all subsets of states which are excitations of the vacuum state by uniformly bounded observables localized in a given finite region of spacetime are compact in the Hilbert space of states. This result, which is in agreement with Haag-Swieca's conjecture, is also given a more precise form in terms of the rate of decrease of the ``N–dimensional thickness' (or approximation number) of such sets of states when N tends to infinity. A similar computation, valid at arbitrarily high energies, is also given for the massive free-field case. Received: 7 February 2003 / Accepted: 5 April 2003 Published online: 13 May 2003 Communicated by H. Araki, D. Buchholz and K. Fredenhagen     

Optical Model Analysis for Elastic Deuteron Scattering on light Nuclei

An optical model analysis for the elastic deuteron scattering on light nuclei (⁷Li. ⁹Be, ¹¹B, ¹²B and ¹⁶O) is studied at energies about 28MeV. Satisfactory fits to the experimental data are found using the volume and the surface absorption nuclear potentials. The effect of varying the resulting parameters on the differential cross-section is discussed.